Improving Blockchain Consistency Bound by Assigning Weights to Random Blocks

Blockchains based on the celebrated Nakamoto consensus protocol have shown promise in several applications, including cryptocurrencies. However, these blockchains have inherent scalability limits caused by the protocol’s consensus properties. In particular, the consistency property demonstrates a tight trade-off between block production speed and the system’s security in terms of resisting adversarial attacks. As such, this paper proposes a novel method called Ironclad, which improves the blockchain consistency bound by assigning a different weight to randomly selected blocks. We apply our method to the original Nakamoto protocol and rigorously prove that such a combination can significantly improve the consistency bound by analyzing the fundamental consensus properties. This kind of improvement enables a much faster block production rate than the original Nakamoto protocol but with the same security guarantee.

Funding: This work was supported in part by the WeBank-Hong Kong University of Science and Technology Joint Lab [Project WEB19EG01-M]. The research of J. Zhang was supported in part by the Hong Kong Research Grants Council [Grants 16208120 and 16214121].

Supplemental Material: The computer code and data that support the findings of this study are available within this article’s supplemental material at https://doi.org/10.1287/opre.2022.0463.